Sandimirov S.S. Catalogue of lakes in the Russian, Finnish and Norwegian Border Area. Finland, Jyvaskyla: Kopijyva Oy, 2008.

(Fig. 75). The maximum concentrations of As, Pb and Cd occur at a depth of 1-3 cm, and the concentrations decrease on moving upwards into the uppermost 1-2 cm layer. The contamination factor values for these elements range from 1.9 to 10.8 (Table 48), i.e. the values correspond to moderate and high contamination. Pb has the highest Cf value. The degree of contamination value (20.7) for Lake Suovaselkajarvi corresponds to considerable contamination. 0 .3 |x g /g CL>IV. "d й 0) e ^20 H 8-10 - "S 0) 6 ^20 i 2 0 jLXg/g 0 - В • о -S &10 - -a <u а "3 сл20 - тЗ $ 2 0 5 1 0 15 n g /g Lake Layer, cm LOI Cu Ni Zn Co Cd Pb As c. Suovaselkajarvi 0-1 59.91 24 25 28 1.4 0.25 12.2 1.7 23-24 31.18 24 13 22 3.0 0.09 1.1 0.68 c, 1.0 1.9 1.2 0.5 2.8 10.8 2.5 20.7 3.5.3. Hydrobiological studies Ichthyofauna. Studies on the fish community of Lake Suovaselkajarvi were conducted in 2005. The most common fish species in the lake are: whitefish ( C oregonus lavaretus), pike (Esoxlucius) and perch ( Perea £uviatilis). Perch is the predominant species (90 %) (Fig. 76)., Grayling ( Thymallus thymallus), burbot ( Lota lota), minnow ( Phoxinus phoxinus) and nine-spine stickleback ( Pungitius pungitius) obviously also inhabit the lake. Fig. 75. Vertical distribution of the concentrations ofNi, As, Cd and Pb (цд/д, dry weight) in the sediment core from Lake Suovaselkajarvi. Table 48. The organic matter contents (LOI, %) and heavy metal concentrations (цд/д, dry weight) in the surface (0- 1cm) and pre-industrial (23-24 cm) sediment layers. Cfand Cdrefer to the contamination factor and degree of contamination values, respectively. Catalogue of Lakes in the Russian, Finnish and Norwegian BorderArea 131